Medical syringe

ABSTRACT

A device for use in surgical procedures formed of a concertina cartridge (1) of a resilient material. The cartridge (1) has a nozzle (5), the throat of which is designed to receive by snap-click action, a projection (9) formed internally of the chamber (1), to hold the cartridge in a collapsed, but resiliently releasable, state as it is compressed to that state under concertina action. The device has applicability to surgical procedures such as blood collection, drug infusion, and balloon catheter inflation while eliminating the dangers of bacterial infection always present when performing such procedures using devices and systems of the prior art.

FIELD OF THE INVENTION

The present invention relates to a device for use in surgical, medicaland therapeutic procedures.

BACKGROUND ART

It is common practice for plastics or rubber tubes to be inserted intothe tissues, cavities, orifices or veins of the human body.

Such tubes (otherwise known as catheters or cannulae) possess twochannels down the central bore of the catheter. Whilst one (the larger)channel, is used for the infusion of fluid into or drainage out of thebody, the other smaller diameter channel communicates with a latexballoon placed concentrically around the catheter shaft and close to theend of the tube which is left within a body cavity, e.g., the urinarybladder.

The other end of the smaller channel is protected by a plastic hubcontaining a displaceable rubber diaphragm which acts as a one-wayvalve. This secondary channel and valved-port permits the inflation ofthe balloon which then effectively engages upon the surrounding tissuesof the body cavity and prevents the catheter from sliding out of thebody.

The technique and procedure for inflating the balloon at the presenttime, involves a series of actions on the part of a nurse or doctor,including the manipulation and breaking open of an ampoule or bottle orsterile water or saline; the opening of a sterile packet containing anhypodermic type plastics syringe; the opening and use of a sterileneedle or plastics quill from a packet to aspirate the contents of theampoule into the syringe; and finally the insertion of the nozzle of thefull hypodermic into the valved-inflation port of the catheter.

Moreover the resistance of the valve diaphragm must be overcome and aprecise volume of fluid discharged into the balloon to achieveinflation, before the hypodermic syringe is removed from the inflationport.

It can be easily seen from the above that numerous components arerequired to perform the task and the risk of bacterial contaminationduring the various stages is an ever present potential problem.

Similarly, another common and important function of plastics tubes whichhave been partially inserted into the body is their use as a portal foraccess to the venous or arterial system.

In these circumstances, a short length of fine-calibre hollow plasticsor rubber tubing is placed, by a variety of techniques, into the lumenor channel of a blood vessel through a small wound in the skin. Thecentral channel of the hollow catheter thereby is able to conduct avariety of physiological fluids into the blood vascular system.

The ends of the cannulae external to the body surface are fitted with aplastics or metal female luer hub which conforms to an InternationalStandard in respect of its internal configuration.

Into this female luer hub, can be fitted a male luer nozzle which alsoconforms to an International Standard specification.

The normal practice is for the male nozzle to be the end component of aninfusion tubing system which slowly delivers fluid from an intravenousbottle or bag, under the influence of gravity or a mechanicalroller-pump. At intervals, in the care of patients, the need for theinfusion system can be dispensed with, in order to make the patientsmore mobile and allow them to walk freely about the wards and corridors.

To achieve this end, the female hub of the intravenous cannula iscovered by a small plastics cap or plug. However, before this isperformed, the cannula tubing must be filled with a saline solution(often containing an anticoagulant agent--heparin) to preventcoagulation of the blood within the cannula and adjacent blood vessels.

This procedure, as in the case of the catheter balloon inflationmanoeuvre, also requires the same range of accessory equipment to beused as previously described in the preceding paragraphs, to accomplishthe final objective.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a device for use in surgicalprocedures which can simultaneously perform all the necessary functionsrequired for the inflation of medical catheter balloons and the asepticocclusion of the hubs of vascular cannulae and avoiding the problems andcomplexities as above described.

It is a further object of the invention to provide a device for use insurgical procedures such as drug infusion and blood collection whichavoids the problems of bacterial infection and, in the case of bloodcollection, also the accidental injection of air into the patient.

According to the invention there is provided a device for use insurgical procedures comprising a cartridge, a nozzle on the cartridgeadapted for connection to a medical catheter and/or tube, the walls ofsaid cartridge being designed to allow the cartridge to be depressed byconcertina action from an expanded state to a collapsed state to expelits contents through said nozzle, and means in the cartridge arranged tobe interengageable with said nozzle as the cartridge moves to saidcollapsed state thereby to hold the cartridge in that state and closethe nozzle.

With this device so defined it is possible simultaneously to inflatemedical catheter balloons and occlude the hubs of vascular cannulaewhich previously required a variety of complicated procedures andaccessory equipment not consonant with the achievement of the desiredobjective of avoidance of bacterial contamination and enhancement ofefficiency and high standards of patient care.

It is also possible to employ the device to perform infusion of drugs,as a blood or body fluid collection device.

A good measure of the range of the objectives and advantages of theinvention will be apparent from the following disclosure directed tomore specific details of some examples whereby the invention may be putinto practical effect.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

Some embodiments of the invention will therefore be describedhereinafter by way of example with reference to the accompanyingdrawings wherein;

FIG. 1 is a sectional view of a device for use in surgical procedures;

FIG. 2 shows the device of FIG. 1 moved from its expanded state as shownin that Figure, to a collapsed locked position;

FIG. 3 is a modified form of the device shown in FIG. 1;

FIG. 4 illustrates in perspective view, a further modification of thedevice for use in surgical procedures shown in either FIG. 1 or FIG. 3;

FIG. 5 is a perspective view of the device according to the inventionmodified for use in the administration of drugs; and

FIG. 6 illustrates how a bank of drug infusion devices may be assembledtogether for a multiple drug infusion procedure employing a syringeinfusion pump.

BEST MODES OF CARRYING OUT THE INVENTION

The device for use in surgical procedures shown in the drawingscomprises a main hollow cartridge chamber 1, the walls 2 of which aredesigned, either in circular, oval or rectangular cross-section, forconcertina action between an expanded state, shown in FIGS. 1 and 3, anda collapsed state, as shown in FIG. 2.

The cartridge chamber 1 and its various component parts to be described,will normally be manufactured in a flexible plastics material usingblow-mould technology to achieve the precise shapes required.

One end wall 3 of the cartridge chamber 1 has a centrally positionedintegrally formed male luer cone shaped nozzle 4 which fits preciselycurrent balloon inflation ports on medical catheters and vascularcannula female luer hubs (not shown).

The internal bore of the nozzle 4 has a depressed peripheral region 5which forms a dilatation 6 near the throat of the nozzle 4 inconjunction with a constriction 7 between the dilatation 6 and the endwall 3 of the cartridge chamber 1.

Centrally positioned on the internal surface of the other end wall 8 ofthe cartridge chamber 1, is a projecting peg or stud 9 in axialalignment with the axis of the nozzle 4.

The stud 9 has a rounded head 10 the largest diametrial portion 11 ofwhich is equal to the diameter of the dilatation 6 in the nozzle 4. Theneck of the stud 9 tapers from a smallest diameter 12, equal to or lessthan the diameter of the constriction 7 in the nozzle 4, to a largestdiameter 14 at its base 15 adjoining the end wall 8 of the cartridgechamber 1.

The outer surface of the end wall 8 of the cartridge chamber 1, see FIG.3, is recessed at 16 conveniently to receive an operator's thumb.Similarly the outer surface of the end wall 3, each side of the nozzle4, is recessed at 17 to accommodate the tips of two fingers of theoperator, and by the combination of the recesses 16 and 17 the operatoris able to apply a safe and controlled continuous pressure when usingthe device as will be explained.

Thus operated with one hand, the device acts as a small totally-closedpump, whereby pressure applied to the end wall 8 by the thumb towardsthe other end wall 3 controlled by the tips of two fingers of the samehand, expells the cartridge contents to be it air or liquid. Thus withliquid in the cartridge chamber 1 depression of the cartridge in the waydescribed will cause the liquid to be ejected via the nozzle 4 through amedical catheter balloon inflation valve port or into an intravascularcatheter.

Once the injection is completed in this way, the head 10 of the stud 9will positively engage the throat of the nozzle 4 as by a snap-fitaction as the portion 11 engages the dilatation 6 behind theconstriction 7 with a pronounced click. The closing action willeffectively prevent the reflux of any of the contained fluid or bodyfluid back into the chamber 1.

Due to the resiliency of the component parts of the device as described,release of the stud 9 from engagement with the throat of the nozzle 4may be effected by simple finger pressure as will be appreciated.

This facility provides an effective hydraulic sealing cap forintravascular devices and prevents re-use and therefore bacterialcontamination of the concertina cartridge. Because fluid contained inthe chamber 1 is totally enclosed as it is ejected, the potential forbacterial contamination is also removed during this injection phase, incontrast to a conventional syringe barrel which has a small but definitespace around the plunger allowing leakage, air entry and the entry ofmicro-organisms.

In a modified form of the device, means may be provided, as shown inFIG. 3, to assist retention of the device in its collapsed state asshown in FIG. 1. This assistive means comprises the provision ofresilient flanges F on the end wall 8 of the chamber 1 carrying catchesC.

The other end wall 3 of the chamber 1 would then have complementaryformations as at H to engage the catches C in the collapsed state.

A further modification of the device according to the invention notshown in the drawings may employ the use of a bayonet catch formed onthe stud 9, the internal bore of nozzle 3 being suitably adapted toengage the bayonet catch in the collapsed state.

The device as described with reference to FIGS. 1 and 3 may be used as asyringe cartridge for the infusion of solutions of drugs of a widevariety of volumns at controlled rates by non-manual compression usingnon-mechanical or electrical infusion pumps.

In this application the precise flow rate of dispensed fluid is criticaland therefore to prevent distortion of the concertina walls of thechamber 1, these walls may be provided with suitably positioned indentsI as shown in the modification of FIG. 4, into which are locatedstiffening rods R which act as guide elements as the cartridge chamberis compressed.

In this application the syringe cartridge will be linked through thenozzle 4 by a short piece of flexible plastics tubing to a cannula orcatheter (not shown) inserted into the body of a patient or animal.

By using such a system the need for complex plastics administration setswhich rely upon gravity for the force of administration would beeliminated. This would be of particular value in patients requiringevacuation from accidents by air, sea or road transport. Currenthypodermic syringes consist of a barrel and a separate plunger thusallowing the potential or bacterial entrance into the syringe chamber.It will be appreciated that the device of the invention avoids thishazard.

For multiple drug infusion applications each cartridge chamber, as shownin FIG. 5, may be provided with means 18, see FIG. 5, engageable with adrive shaft 19 of a mechanical or electrical infusion pump (not shown).

As shown at 18 in FIG. 5, the engagement means in a representativecartridge may take one of several forms, for example, square, circular,triangular or crossed shaped recesses.

In this case the drive shaft 19 shown in FIG. 5, of the infusion pumpwould be provided with end pieces 20 shaped for reception within therecesses 18 as appropriate.

The particular shaped recess in a representative drug infusion cartridgewould then act as an identification of the drug in that cartridge sothat a whole bank of cartridges 1 could be mounted to an appropriatelydesigned and coded infusion pump, shown schematically as 21 in FIG. 6,and operated by micro-processor means (not shown) on a totallyautomatic, non-manual and precisely controlled basis.

The invention may also be used in another form as a blood or body fluidcollection device. In this application the closure mechanism isillustrated in FIGS. 1, 2 and 3 allows the device to be delivered to thepatients in a collapsed state and thus empty of any air. In this way thedanger of accidental injection into the patient is avoided. For thisapplication, the rearward end of the cartridge may be extended as aflange (not shown) for gripping between finger and thumb during theblood collection procedure.

In another form the device can be used to instill antiseptic solutionsthrough the tap mechanisms of plastics urinary drainage collection bags.This effectively provides an antiseptic locking mechanism and preventsbacterial entry into the sterile urinary drainage system.

Other modifications will be readily apparent to one skilled in the artbut such will fall within the scope of the inventions defined in thefollowing claims.

I claim:
 1. A device for use in surgical procedures comprising:acartridge chamber having opposed end walls and a peripheral side wall; anozzle extending from one of said end walls of said cartridge chamberadapted for connection to medical catheter means, said nozzle having athroat; and a shaped projection on the inside of said side wall of saidcartridge chamber opposite said throat of said nozzle, said shapedprojection having a peripheral recess; said peripheral side wall of saidcartridge chamber having pleats to allow said cartridge chamber to bedepressed by concertina action from an expanded state to a collapsedstate to expel its contents through said nozzle; and said throat beingresilient and having a constriction complimentary thereto in the throatof said nozzle for engaging said peripheral recess in said shapedprojection when said cartridge chamber is in the collapsed state.
 2. Adevice as claimed in claim 1 wherein said end wall of said cartridgechamber carrying said shaped projection is provided with exteriorlyformed resilient projections which engage complimentary formations onthe exterior of said other end wall of said cartridge chamber in thecollapsed state of said cartridge chamber.
 3. A device as claimed inclaim 1, formed wholly of a resilient plastic material.
 4. A device foruse in surgical procedures comprising:a cartridge chamber having opposedend walls and a peripheral side wall; a nozzle extending from one ofsaid end walls of said cartridge chamber adapted for connection tomedical catheter means, said nozzle having a throat, said peripheralside wall of said cartridge chamber having pleats to allow saidcartridge chamber to be depressed by concertina action from an expandedto a collapsed state to expel its contents through said nozzle; andmeans in said cartridge chamber for arranging for interengaging withsaid nozzle as said cartridge chamber moves to said collapsed statethereby to hold said cartridge chamber in that state and close saidnozzle, the outer edges of said pleats of said peripheral side wallbeing provided with indents carrying stiffening rods which form guideelements for said cartridge chamber during movement between the expandedand collapsed states.
 5. A device as claimed in claim 4, formed whollyof a resilient plastic material.
 6. A device for use in surgicalprocedures comprising:a cartridge chamber having opposed end walls and aperipheral side wall; a nozzle extending from one of said end walls ofsaid cartridge chamber adapted for connection to medical catheter means,said nozzle having a throat, said peripheral side wall of said cartridgechamber having pleats to allow said cartridge chamber to be depressed byconcertina action from an expanded state to a collapsed state to expelits contents through said nozzle; and means in said cartridge chamberarranged for interengaging with said nozzle as said cartridge chambermoves to said collapsed state thereby to hold said cartridge chamber inthat state and close said nozzle; said end wall of said cartridgechamber opposite said nozzle being provided with a recess, said recessbeing shaped to receive a complimentary shaped end piece of the driveshaft of a syringe infusion pump to enable automatic controlleddepression of said cartridge chamber thereby, and said recess being ofvariable cross-section from cartridge chamber to cartridge chamber, soproviding identification means for a drug compound within said cartridgechamber.
 7. A device for use in surgical procedures comprising:acartridge chamber having opposed end walls and a peripheral side wall; anozzle extending from one of said end walls of said cartridge chamberadapted for connection to medical catheter means, said nozzle having athroat, said peripheral side wall of said cartridge chamber havingpleats to allow said cartridge chamber to be depressed by concertinaaction from an expanded state to a collapsed state to expel its contentsthrough said nozzle; and means in said cartridge chamber arranged forinterengaging with said nozzle as said cartridge chamber moves to saidcollapsed state thereby to hold said cartridge chamber in that state andclose said nozzle; said end wall of said cartridge chamber opposite saidnozzle being provided with a recess, said recess having a particulargeometric shape representative of the identity of a particular drug andadapted to receive the complimentary shaped end piece of the drive shaftof a syringe infusion pump to enable automatic controlled depression ofsaid cartridge chamber thereby.